如何在scala中将列表转换为Json数组

这是我的代码，这里的返回类型是list，但list转换为array，返回类型更改为string

    @RequestMapping(value =Array( "/StandardChange.html"))
    @ResponseBody
    def  findDivisionOfStandards(@RequestParam  divisionid:Long):List[Division] ={

     var division:List[Division]= null
     if (divisionid != null) {

        division  = divisionService.findDivisionByStandardId(divisionid)            
    }       
     division  
    }

我试过了，但没用

返回类型更改为List到String，值更改为List到Json数组

  @RequestMapping(value =Array( "/StandardChange.html"))
  @ResponseBody
    def  findDivisionOfStandards(@RequestParam  divisionid:Long):String ={

      var division:List[Division]= null

      if (divisionid != null) {

           division  = divisionService.findDivisionByStandardId(divisionid)         

        }   
       var divisionjsonArray=  division.toArray     **json convert should be here**

      divisionjsonArray
    }

compact(render(decompose(division)))